DESCRIPTION:(Verbatim from application) Muscle wasting (sarcopenia) has adverse effects on nearly all of the nation's elderly, and because it causes additional inactivity, sarcopenia often initiates a debilitating positive feedback loop accelerating the rate of muscle loss. Additional exercise interventions are needed that: 1) are non-strenuous (low intensity), to assure compliance by those who would benefit from them; 2) maximize stress to the muscles to insure gains in muscle mass and strength while preserving or improving muscle blood flow; 3) focus on those muscle deficits that most directly impact daily living activities; and 4) minimize cardio-respiratory support, as the elderly often have respiratory and/or cardiac impairments that accompany (and exacerbate) sarcopenia. Data from three previous studies suggest that high-force eccentric exercise may be an ideal sarcopenia intervention as it has all those characteristics listed above. Specific Aim 1 will establish the practicality of high-force eccentric training in normal elderly subjects. We intend to demonstrate that high-force eccentric training on a recumbent stationary bicycle is comfortable and safe in elderly, "at risk" individuals with little discomfort, no muscle damage or injury and that it is an activity that will be perceived as non-strenuous. Specific Aim 2 will demonstrate that high-force eccentric training results in increases in muscle mass and strength equal to or exceeding that resulting from resistance training, but at low exercise intensities. Specific Aim 3 will establish the muscle ultra structural changes including fiber type, fiber-specific cross-sectional area change and capillarity, that accompany eccentric training. Specific Aim 4 will demonstrate the consequence of increased muscle mass/strength is an enhanced ability to perform daily tasks of everyday living, in particular problematic eccentric contractions such as in descending stairs. These improvements may also be in the form of increased reserve of strength or safety factor to accomplish these tasks. High-force eccentric training has not been exploited as an intervention tool, however it may be ideal for sarcopenia. With one more intervention in the arsenal against sarcopenia, it should be possible to better tailor individual exercise programs to halt or in many instances reverse the debilitating muscle pathophysiology and functional consequences of muscle wasting in the elderly.